Journal of Microbiology

Research Support, Non-U.S. Gov't

Cloning and Expression Analysis of a Chitinase Gene Crchi1 from the Mycoparasitic Fungus Clonostachys rosea (syn. Gliocladium roseum): Zhongwei Gan , Jinkui Yang , Nan Tao , Zefen Yu , Ke-Qin Zhang; J. Microbiol. 2007;45(5):422-430.; DOI: https://doi.org/2594 [pii]

Abstract: Clonostachys rosea (syn. Gliocladium roseum) is a well-known biocontrol agent and widely distributed around the world. In this study, an endochitinase gene Crchi1 was isolated from the mycoparasitic fungus C. rosea using the DNA walking strategy. The Crchi1 ORF is 1,746 bp long and interrupted by three introns. The cloned gene Crchi1 encodes 426 amino acid residues and shares a high degree of similarity with other chitinases from entomopathogenic and mycoparasitic fungi. Several putative binding sites for transcriptional regulation of Crchi1 in response to carbon (5''-SYGGRG-3'') and nitrogen (5''-GATA-3'') were identified in the upstream of Crchi1. Expression of Crchi1 gene in different carbon sources was analyzed using real-time PCR (RT-PCR). We found that the Crchi1 expression was suppressed by glucose but strongly stimulated by chitin or solubilized components of the cell wall from Rhizoctonia solani. Phylogenetic analysis of chitinases from entomopathogenic and mycoparasitic fungi suggests that these chitinases have probably evolved from a common ancestor.

Transcriptional Induction of a Carbon Starvation Gene during Other Starvation and Stress Challenges in Pseudomonas putida MK1: A Role of a Carbon Starvation Gene in General Starvation and Stress Responses: Chitra, Subramanian+ , Lee, Ho Sa , Kim, Young Jun; J. Microbiol. 1999;37(3):141-147.

Abstract: Thirteen transcriptionally-fused carbon starvation mutants, derived from Pseudomonas putida ATCC 12633, were analyzed for their survivability and transcriptional induction profiles upon carbon starvation. One of these mutants, MK114, which exhibited the lowest survivability and the highest induction rate, was selected and further examined under different starvation (nitrogen and phosphate) and stress (osmolarity, H₂O₂, salts, alcohol, and heat) conditions. Under all tested conditions MK114 induced β-galactosidase activity, implying that the interrupted gene (cst114) is a general starvation and stress response gene. The rate of induction ranged from 2.6-fold for phosphate starvation to 3.7-fold for osmotic shock. The mini-Tn5 flanking DNA was cloned from the chromosome of MK114. The cloned DNA fragment exhibited carbon starvation activity, indicating that this fragment contains a carbon starvation-related promoter region. This region was partially sequenced. Possible physiological roles of Cst114 in a carbon sensing mechanism and in other stress responses are also discussed.

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